本篇內(nèi)容介紹了“MySQL誤刪root用戶怎么恢復”的有關知識，在實際案例的操作過程中，不少人都會遇到這樣的困境，接下來就讓小編帶領大家學習一下如何處理這些情況吧！希望大家仔細閱讀，能夠學有所成！
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一個朋友在領導要求他刪除root@127.0.0.1，root@'%'等用戶，只保留root@localhost時，
他寫了一條類似delete from mysql.user where user='root'的命令……
注意，他并沒有寫 “and host=”的條件，導致悲劇發(fā)生，并且還flush了授權。
以下模擬誤刪操作，嘗試做恢復：
MySQL版本：
MySQL 5.5.49
模擬誤刪操作：
mysql> DELETE FROM mysql.user WHERE user='root';
Query OK, 1 row affected (0.01 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.01 sec)
解決思路：
新安裝或者初始化一個新的實例（與誤刪操作的MySQL版本最好一致）
初始化好后，啟動實例，并以root@localhost用戶登錄，然后設置密碼：
新實例上：
mysql> SELECT current_user();
+----------------+
| current_user() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)
mysql> SET PASSWORD=password('123456');
Query OK, 0 rows affected (0.00 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
將存放在mysql.user里的root@localhost用戶信息查詢出：
mysql> SELECT * FROM mysql.user WHERE user='root' AND host='localhost' INTO OUTFILE '/tmp/root.txt';
Query OK, 1 row affected (0.00 sec)
對于誤刪操作的實例：
首先將之前查詢出的/tmp/root.txt文件傳到該機上，此處傳到同目錄下，操作略。
然后要停掉mysqld，并繞過授權表啟動：
可能無法通過mysqladmin shutdown來停止，此處直接kill掉mysqld_safe與mysqld，操作略。
然后啟動：
[root@vm02 ~]# mysqld_safe --skip-grant-tables &
[1] 2957
[root@vm02 ~]# 160819 17:00:30 mysqld_safe Logging to '/data/mysql_log/err-log.err'.
160819 17:00:30 mysqld_safe Starting mysqld daemon with databases from /data/mysql
進入mysql：
[root@vm02 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.5.49-log MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> SELECT user(),current_user();
+--------+----------------+
| user() | current_user() |
+--------+----------------+
| root@ | @ |
+--------+----------------+
1 row in set (0.00 sec)
可以查看一下mysql.user表，已經(jīng)沒有了誤刪的root用戶，只剩下xxx@'ip1'，yyy@'ip2'，這樣的業(yè)務用戶：
mysql> SELECT user,host FROM mysql.user;
+------+---------------+
| user | host |
+------+---------------+
| xxx | 192.168.1.185 |
| yyy | 192.168.1.187 |
+------+---------------+
2 rows in set (0.00 sec)
將之前的新實例的mysql.user表中的root@localhost信息導入mysql.user：
mysql> LOAD DATA INFILE '/tmp/root.txt' INTO TABLE mysql.user;
Query OK, 1 row affected (0.04 sec)
Records: 1 Deleted: 0 Skipped: 0 Warnings: 0
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT user,host FROM mysql.user WHERE user='root' AND host='localhost';
+------+---------------+
| user | host |
+------+---------------+
| root | localhost |
+------+---------------+
1 rows in set (0.00 sec)
退出到shell環(huán)境，關閉以skip-grant-tables方式啟動的mysqld：
此時已經(jīng)可以用mysqladmin來關閉mysqld了：
[root@vm02 tmp]# mysqladmin -uroot -p123456 shutdown
160819 17:08:08 mysqld_safe mysqld from pid file /data/mysql/mysql-pid ended
[1]+ Done mysqld_safe --skip-grant-tables (wd: ~)
(wd now: /tmp)
[root@vm02 tmp]# ps -ef|grep mysql
root 3938 1973 0 17:08 pts/0 00:00:00 grep mysql
再重新啟動mysqld：
[root@vm02 tmp]# mysqld_safe &
[1] 3939
[root@vm02 tmp]# 160819 17:08:53 mysqld_safe Logging to '/data/mysql_log/err-log.err'.
160819 17:08:53 mysqld_safe Starting mysqld daemon with databases from /data/mysql
已經(jīng)可以正常使用了，密碼是之前在初始化的新實例設置的：
[root@vm02 tmp]# mysql -uroot -p123456
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.5.49-log MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> SELECT user(),current_user();
+----------------+----------------+
| user() | current_user() |
+----------------+----------------+
| root@localhost | root@localhost |
+----------------+----------------+
1 row in set (0.00 sec)
查看一下權限，可以對比一下，與之前的無異：
mysql> SHOW GRANTS;
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION |
+----------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
“MySQL誤刪root用戶怎么恢復”的內(nèi)容就介紹到這里了，感謝大家的閱讀。如果想了解更多行業(yè)相關的知識可以關注創(chuàng)新互聯(lián)網(wǎng)站，小編將為大家輸出更多高質(zhì)量的實用文章！
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